Information code reading device, information code reading method, and information code reading program

Abstract

A portable terminal device (14) is a QR code reading device that reads, by illuminating with light of a predetermined wavelength other than visible light, a transparent QR code (10) that cannot be visually recognized by visible light. The portable terminal device (14) guides the image-capturing operation of an operator by a guide unit so that the influence of infrared light is mitigated when performing image-capturing, and while irradiating infrared light by an infrared light irradiation unit (24), reads the transparent QR code (10) by a camera (22) capturing an image of the transparent QR code (10).

Description

Information code reading device, information code reading method, and information code reading program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-125001, filed on July 31, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to an information code reading device, an information code reading method, and an information code reading program.

[0003] Currently, various information codes are in widespread use, including two-dimensional codes such as QR Codes (registered trademark) and one-dimensional codes such as barcodes.

[0004] Among these information codes, transparent two-dimensional codes that are invisible to humans are also being developed. There are various reasons for using transparent two-dimensional codes. For example, printing multiple two-dimensional codes on a product is undesirable from a design perspective, and transparent two-dimensional codes can store information about distribution that consumers do not need to know.

[0005] Japanese Patent Application Laid-Open No. 2003-144999 describes printing a transparent two-dimensional code on paper using toner that does not absorb visible light but does absorb infrared light.

[0006] JP 2018-89840 A

[0007] In Patent Document 1, the information code is actually difficult to read even when photographed with a camera because it is not visible with visible light.

[0008] An object of the present disclosure is to provide an information code reading device, an information code reading method, and an information code reading program that are capable of reading transparent information codes that cannot be recognized with visible light.

[0009] The present disclosure employs the following technical solutions to solve the above problems. The reference symbols in parentheses in the claims and in this section are merely examples showing the correspondence with the specific solutions described in the embodiments below as one aspect, and do not limit the technical scope of the present disclosure.

[0010] An information code reading device according to one embodiment of the present disclosure is an information code reading device that reads information codes that cannot be seen with visible light by illuminating them with light of a predetermined wavelength other than visible light, and includes an imaging unit that images a subject, an irradiation unit that irradiates light of the predetermined wavelength, and a guidance unit that guides an operator in performing an imaging operation to reduce the effects of light of the predetermined wavelength when the information code is photographed by the imaging unit.

[0011] Transparent information codes, which are information codes that cannot be seen with visible light, can be read by illuminating them with light of a specific wavelength other than visible light, such as infrared or ultraviolet light. However, reading such transparent information codes is difficult, and the reason for this difficulty has not been clear. The present inventor has newly discovered that this is due to the specific wavelength of light that illuminates the transparent information code, and that it is necessary to mitigate the influence of the specific wavelength of light when photographing a transparent information code.

[0012] Therefore, when photographing a transparent information code, the information code reader of this configuration guides the operator to photograph the transparent information code in a way that reduces the influence of light of a predetermined wavelength.By photographing the transparent information code according to the guidance, the information code reader of this configuration can read the transparent information code.

[0013] In the above-mentioned information code reading device, the guidance unit may guide the operator's photographing operation so that the photographing position of the information code by the photographing unit is a predetermined position based on the positional relationship between the photographing unit and the irradiation unit.

[0014] The present inventors have newly discovered that one of the reasons why it is difficult to read transparent information codes is the influence of reflection of light of a predetermined wavelength irradiated from an irradiation unit. In other words, even if an operator photographs a transparent information code with an imaging unit, if the image photographed by the imaging unit is strongly influenced by reflection of light from the irradiation unit, the transparent information code cannot be read. According to this configuration, the operator is guided in performing the imaging operation so that the photographing position of the transparent information code is a predetermined position that is less influenced by light of a predetermined wavelength based on the positional relationship between the imaging unit and the irradiation unit, thereby making it possible to more reliably read transparent information codes.

[0015] In the above-mentioned information code reading device, a display unit is provided that displays the image captured by the photographing unit, and the guidance unit may enlarge and display a partial area of ​​the image captured by the photographing unit on the display unit so that the photographing position of the information code by the photographing unit is the predetermined position.

[0016] With this configuration, the operator moves the information code reader so that the transparent information code is displayed in the center of the enlarged display. Therefore, with this configuration, the transparent information code is photographed in an appropriate position that is less susceptible to the effects of reflected light, enabling more reliable reading of the transparent information code.

[0017] The above-mentioned information code reading device may be provided with a location determination unit that determines whether the location where the information code was photographed is indoors or outdoors, and the guidance unit may guide the operator in performing the photographing operation based on the determination result by the location determination unit.

[0018] The present inventors have newly discovered that one of the reasons why it is difficult to read transparent information codes is the effect of sunlight containing certain wavelengths such as infrared and ultraviolet rays. With this configuration, the operator's shooting operation is guided based on whether the shooting location is indoors or outdoors, making it possible to read transparent information codes more reliably.

[0019] In the above information code reading device, the guiding unit may guide the operator in the photographing operation so that the photographing position of the information code by the photographing unit is a predetermined position, based on the determination result by the location determination unit.

[0020] According to this configuration, the positional relationship between the transparent information code and the photographing unit is set to an appropriate positional relationship based on whether the transparent information code is indoors or outdoors, and the transparent information code is photographed, so that the transparent information code can be read more reliably.

[0021] In the above information code reading device, the guiding unit may guide the operator in the photographing operation so that the distance between the information code and the photographing unit becomes a distance based on the determination result by the location determination unit.

[0022] According to this configuration, the transparent information code is photographed at an appropriate distance where the influence of light of a predetermined wavelength is reduced, so that the transparent information code can be read more reliably.

[0023] In the above information code reader, the distance may be shorter when the information code is photographed outdoors than when the information code is photographed indoors.

[0024] According to this configuration, the influence of light of a predetermined wavelength is reduced when photographing outdoors, so that the transparent information code can be read more reliably.

[0025] In the above information code reading device, the guiding unit may guide the operator in the photographing operation so as to adjust the angle between the photographing unit and the information code.

[0026] According to this configuration, the imaging angle is optimized, making it possible to read the transparent information code more reliably.

[0027] In the above-mentioned information code reading device, the guidance unit may guide the operator in the photographing operation so as to increase the angle when the distortion of the information code photographed by the photographing unit is relatively small, and to decrease the angle when the distortion is relatively large.

[0028] According to this configuration, distortion of the photographed transparent information code is reduced, so that the transparent information code can be read more reliably.

[0029] In the above-mentioned information code reading device, when the location where the information code is photographed is outdoors and the information code is photographed but not recognized, the guidance unit may guide the photographer's direction of photography so that sunlight does not illuminate the information code.

[0030] According to this configuration, the influence of light of a predetermined wavelength is reduced when photographing outdoors, so that the transparent information code can be read more reliably.

[0031] An information code reading method according to one aspect of the present disclosure is a method for reading an information code that cannot be seen with visible light by illuminating it with light of a predetermined wavelength other than visible light, in which a guidance unit guides an operator in performing a photographing operation to take a photograph that reduces the influence of light of the predetermined wavelength, and an illumination unit irradiates the information code with light of the predetermined wavelength while an imaging unit photographs the information code to read the information code.

[0032] An information code reading program according to one embodiment of the present disclosure is an information code reading program possessed by an information code reading device that reads information codes that cannot be seen with visible light by illuminating them with light of a predetermined wavelength other than visible light, and causes a computer to function as a guidance unit that guides an operator in performing a photographing operation so as to perform a photograph that reduces the effects of light of the predetermined wavelength when photographing the information code with a photographing unit that photographs a subject.

[0033] According to the present disclosure, it is possible to read transparent information codes that cannot be recognized with visible light.

[0034] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. FIG. 1 is a schematic diagram of a transparent QR code and a portable terminal device according to an embodiment. FIG. 2 is a functional block diagram related to reading a transparent QR code in the portable terminal device according to an embodiment. FIG. 3 is an external view of an enlarged screen display of the portable terminal device according to an embodiment, where (A) is the screen display before enlargement and (B) is the screen display after enlargement. FIG. 4 is an external view showing the shooting angle of a transparent QR code by the portable terminal device according to an embodiment. FIG. 5 is a flowchart showing the flow of a transparent QR code reading process according to an embodiment. FIG. 6 is a flowchart showing the flow of a process for changing the shooting direction of an operator according to an embodiment.

[0035] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the embodiments described below are examples of how the present disclosure may be implemented, and the present disclosure is not limited to the specific configurations described below. When implementing the present disclosure, specific configurations according to the embodiments may be appropriately adopted.

[0036] FIG. 1 is a schematic diagram of a printed matter 12 on which a transparent QR code 10 of this embodiment is printed, and a mobile terminal device 14.

[0037] The transparent QR code 10 is an information code that cannot be seen with visible light and can be read by illuminating it with light of a predetermined wavelength other than visible light. In other words, the transparent QR code 10 printed on the printed matter 12 becomes visible when illuminated with light of a predetermined wavelength other than visible light.

[0038] The predetermined wavelength is, for example, a wavelength in the infrared region (hereinafter referred to as "infrared light"). That is, the transparent QR code 10 of this embodiment is read by photographing it while illuminated with infrared light. For this reason, the transparent QR code 10 of this embodiment is printed on the printed matter 12 using ink that absorbs infrared light but not visible light. Furthermore, although the transparent information code is a QR code in this embodiment, this is merely an example, and other one-dimensional codes such as two-dimensional codes or barcodes may also be used.

[0039] The printed matter 12 is not limited as long as it is an object on which the transparent QR code 10 can be printed. The transparent QR code 10 may be printed on a sticker or the like, and the sticker may be attached to another object.

[0040] The mobile terminal device 14 is a portable information processing device such as a smartphone or tablet terminal, and has a function of reading QR codes. Note that the mobile terminal device 14 may be a dedicated reader for reading the transparent QR code 10 without a calling function.

[0041] The mobile terminal device 14 includes a computing device such as a CPU (Central Processing Unit) capable of executing programs, a storage device such as an SSD (Solid State Drive), a communication device for connecting to the Internet or an intranet, and various connectors. The mobile terminal device 14 also includes a touch panel display 20 that displays images and accepts operations for the mobile terminal device 14, a camera 22 that captures an image of a subject, an infrared light emitting unit 24 that irradiates infrared light, and an operation unit 26 that accepts operations for the mobile terminal device 14.

[0042] The mobile terminal device 14 is provided with a touch panel display 20 on one side, i.e., the front side, and with a camera 22 and an infrared light emitting unit 24 on the other side, i.e., the back side. In the mobile terminal device 14 of this embodiment, as an example, the camera 22 is provided at the top right when viewed from the front, and the infrared light emitting unit 24 is provided at the top left on the back side.

[0043] In this embodiment, the operator of the mobile terminal device 14 reads the information recorded in the transparent QR code 10 by shining infrared light from the infrared light emitting unit 24 onto the transparent QR code 10 and photographing the transparent QR code 10 with the camera 22. At this time, the transparent QR code 10 is displayed on the touch panel display 20 so that it can be seen by the operator.

[0044] However, it was difficult to read the transparent QR code 10, and the reason for this difficulty was unclear. The present inventor has newly discovered that this is due to the light of a specific wavelength (infrared light in this embodiment) illuminating the transparent QR code 10, and that when photographing the transparent QR code 10, it is necessary to mitigate the influence of the light of the specific wavelength.

[0045] Therefore, the mobile terminal device 14 of this embodiment performs a guidance process that guides the operator in the photographing operation to perform photographing that reduces the influence of infrared light when photographing the transparent QR code 10 with the camera 22. The operator photographs the transparent QR code 10 according to this guidance, and the mobile terminal device 14 can read the transparent QR code 10.

[0046] FIG. 2 is a functional block diagram of the portable terminal device 14 regarding the transparent QR code reading function.

[0047] The mobile terminal device 14 includes a touch panel display 20, a camera 22, an infrared light emitting unit 24, a communication unit 30, a memory unit 32, a QR code recognition unit 34, a photography location determination unit 36, and a guidance unit 38.

[0048] The communication unit 30 transmits and receives information to and from other information processing devices via the Internet or the like.

[0049] The storage unit 32 stores a program and various data related to reading the transparent QR code 10 .

[0050] The QR code recognition unit 34 recognizes the transparent QR code 10 from the image data captured by the camera 22. The QR code recognition unit 34 performs a decoding process to decode the information recorded in the recognized transparent QR code 10.

[0051] The photographing location determination unit 36 ​​determines whether the photographing location of the transparent QR code 10 is indoors or outdoors. The photographing location is determined based on the illuminance detected by the camera 22.

[0052] When the transparent QR code 10 is photographed by the camera 22, the guiding unit 38 performs a guiding process to guide the operator in the photographing operation so as to perform photographing in a way that reduces the influence of infrared light.

[0053] Here, the guidance process executed by the guidance unit 38 of this embodiment will be described. Note that the guidance process of this embodiment includes a plurality of processes. The guidance unit 38 may execute at least one of the following plurality of guidance processes.

[0054] First, the present inventors have newly discovered that one of the reasons why it is difficult to read the transparent QR code 10 is the influence of reflection of infrared light irradiated from the infrared light irradiator 24. In other words, even if an operator photographs the transparent QR code 10 with the camera 22, the transparent QR code 10 cannot be read if the image photographed by the camera 22 is strongly influenced by reflection of the irradiated infrared light. For example, an operator typically adjusts the positional relationship between the camera 22 and the transparent QR code 10 so that the transparent QR code 10 is displayed in the central region of the touch panel display 20. However, with this positional relationship, the transparent QR code 10 may not be readable due to the influence of reflection of the infrared light irradiated from the infrared light irradiator 24.

[0055] Therefore, the guidance process of this embodiment guides the operator in performing the photographing operation so that the photographing position of the transparent QR code 10 by the camera 22 is a predetermined position, based on the positional relationship between the camera 22 and the infrared light irradiating unit 24. In other words, the guidance process guides the operator in performing the photographing operation so that the transparent QR code 10 is positioned at an appropriate photographing position that is less susceptible to the influence of the infrared light irradiated by the infrared light irradiating unit 24, in other words, at a position that avoids reflection of the infrared light from the infrared light irradiating unit 24.

[0056] The optimal photographing position for the transparent QR code 10 varies depending on the positional relationship between the camera 22 and the infrared light emitting unit 24. Therefore, the mobile terminal device 14 stores an appropriate photographing position for the transparent QR code 10 based on the positional relationship between the camera 22 and the infrared light emitting unit 24. The guidance process then guides the operator in the photographing operation based on the positional relationship between the camera 22 and the infrared light emitting unit 24 so that the transparent QR code 10 is positioned in a position that avoids reflection of infrared light, such as the upper right or lower left side of the touch panel display 20.

[0057] In the guidance process of this embodiment, a partial area of ​​the image captured by the camera 22 is enlarged and displayed on the touch panel display 20 so that the position where the transparent QR code 10 is captured by the camera 22 is a predetermined position.

[0058] 3A and 3B are external views of the enlarged screen display of the mobile terminal device 14 according to the present embodiment. Fig. 3A shows the screen display before enlargement, and Fig. 3B shows the screen display after enlargement. Note that the arrows A and B in Fig. 3 do not necessarily have to be displayed on the touch panel display 20.

[0059] 3, the infrared light emitting unit 24 is provided at the upper left when viewed from the front of the mobile terminal device 14, so the reflected infrared light is strongest at the upper left of the touch panel display 20 and weakest at the lower right of the touch panel display 20. For this reason, as indicated by arrow A in FIG. 3(A), it is preferable that the transparent QR code 10 be displayed and read at a position at the lower right of the touch panel display 20.

[0060] Therefore, the mobile terminal device 14 of this embodiment virtually divides the touch panel display 20 into four parts, top, bottom, left, and right, and displays an enlarged view of the lower right area where the reflected infrared light is weakest, as shown in Figure 3(B). As the lower right area of ​​the touch panel display 20 is enlarged, the operator moves the mobile terminal device 14 in the direction of arrow B so that the transparent QR code 10 is displayed in the center of the enlarged view. As a result, the transparent QR code 10 is photographed in an appropriate position that is less susceptible to the influence of reflected light, enabling the transparent QR code 10 to be read more reliably.

[0061] The guidance process for locating the photographing position of the transparent QR code 10 by the camera 22 at an appropriate predetermined position is not limited to the enlarged display. For example, the guidance process may guide the display position of the transparent QR code 10 by displaying an arrow on the touch panel display 20. The guidance process may also guide the operator by outputting a voice from the mobile terminal device 14, such as "Please display the transparent QR code in the lower right corner of the touch panel display."

[0062] Furthermore, the present inventors have newly discovered that sunlight containing infrared light, ultraviolet light, etc., can make it difficult to read the transparent QR code 10. Therefore, the guidance process of this embodiment guides the operator in the photographing operation based on whether the operator is indoors or outdoors.

[0063] That is, since the intensity of sunlight differs indoors and outdoors, the influence of sunlight on reading the transparent QR code 10 differs. For this reason, the guidance process guides the operator in the photographing operation based on whether the operator is indoors or outdoors. This makes it possible for the portable terminal device 14 of this embodiment to read the transparent QR code 10 more reliably.

[0064] For example, the guidance process guides the operator in performing a photographing operation so that the photographing position of the transparent QR code 10 by the camera 22 is a predetermined position based on the determination result by the photographing location determination unit 36. Specifically, as described above, the guidance process guides the operator in performing a photographing operation so that the display position of the transparent QR code 10 is an appropriate position (within a predetermined area) on the touch panel display 20. As a result, the positional relationship between the transparent QR code 10 and the camera 22 is set to an appropriate positional relationship based on whether the camera 22 is indoors or outdoors, and the transparent QR code 10 is photographed, so that the transparent QR code 10 can be read more reliably.

[0065] As described above, the appropriate display position of the transparent QR code 10 also differs depending on the relative positions of the camera 22 and the infrared light emitting unit 24. Therefore, the mobile terminal device 14 stores an appropriate display position of the transparent QR code 10 based on the combination of the relative positions of the camera 22 and the infrared light emitting unit 24 and the shooting location (indoors or outdoors).

[0066] For example, in the mobile terminal device 14 of this embodiment, if the transparent QR code 10 is photographed indoors, the appropriate display position for the transparent QR code 10 is the bottom right of the touch panel display 20. On the other hand, if the transparent QR code 10 is photographed outdoors, the appropriate display position for the transparent QR code 10 is the top left of the touch panel display 20.

[0067] If the transparent QR code 10 is photographed outdoors, the appropriate display position of the transparent QR code 10 may be determined taking into account the position of the sun at the photographing location. The position of the sun at the photographing location can be determined from, for example, the photographing date and time, the latitude and longitude of the photographing location, etc. The photographing date and time is obtained from the calendar function and clock function of the mobile terminal device 14. The latitude and longitude of the photographing location are obtained from the GPS of the mobile terminal device 14.

[0068] The guidance process also guides the operator in the photographing operation so that the photographing distance, which is the distance between the transparent QR code 10 and the camera 22, becomes the optimal photographing distance based on the determination result by the photographing location determination unit 36. This guidance process allows the transparent QR code 10 to be photographed at an appropriate distance that reduces the effects of infrared light, allowing the mobile terminal device 14 to read the transparent QR code 10 more reliably.

[0069] Note that the influence of sunlight is greater outdoors than indoors, and reading the transparent QR code 10 tends to become more difficult when the shooting distance is long during outdoor photography. This is because the longer the shooting distance outdoors, the stronger the sunlight illuminating the transparent QR code 10 becomes. Therefore, the optimal shooting distance when photographing a transparent QR code outdoors is shorter than when photographing it indoors. For example, the optimal shooting distance indoors is 11 cm, while the optimal shooting distance outdoors is 8 cm. This reduces the influence of infrared light during outdoor photography, allowing the mobile terminal device 14 to more reliably read the transparent QR code 10.

[0070] The optimum shooting distances for indoors and outdoors are stored in the mobile terminal device 14. The guidance process guides the operator in the shooting operation by displaying the optimum shooting distance based on the determination result by the shooting location determination unit 36 ​​on the touch panel display 20, outputting the optimum shooting distance by voice, etc.

[0071] The guidance process also guides the operator in the photographing operation to adjust the photographing angle between the camera 22 and the transparent QR code 10. When the photographing angle changes, the recognition state of the transparent QR code 10 using reflected infrared light also changes. Therefore, by optimizing the photographing angle, the mobile terminal device 14 can more reliably read the transparent QR code 10.

[0072] 4 is a schematic diagram showing the imaging angle of the transparent QR code 10. The imaging angle is set to 0° when the mobile terminal device 14 is parallel to the transparent QR code 10. When there is no reflected infrared light, the imaging angle of 0° is preferable. On the other hand, when there is reflected light, it is preferable to increase the imaging angle. As described above, the present inventors have newly discovered that the greater the influence of reflected light, the more preferable it is to increase the imaging angle when imaging the transparent QR code 10. For this reason, the guidance process may guide the operator to adjust the imaging angle by displaying an image or outputting audio when imaging the transparent QR code 10.

[0073] On the other hand, the larger the shooting angle, the more distorted the transparent QR code 10 is photographed, and the lower the recognition performance of the transparent QR code 10. For this reason, the shooting angle may be adjusted to an optimal angle, taking into consideration the distortion of the photographed transparent QR code 10.

[0074] Therefore, the guidance process guides the operator in the photographing operation so that the photographing angle is increased when the distortion of the transparent QR code 10 photographed by the camera 22 is relatively small, and the photographing angle is decreased when the distortion is relatively large. This reduces the distortion of the photographed transparent QR code 10, allowing the mobile terminal device 14 to more reliably read the transparent QR code 10. The magnitude of distortion of the photographed transparent QR code 10 is determined based on predetermined criteria through image analysis of the transparent QR code 10.

[0075] 5 is a flowchart showing the flow of the transparent QR code reading process of this embodiment. The transparent QR code reading process is executed by a program (transparent QR code reading application) stored in a recording medium such as the storage unit 32 provided in the mobile terminal device 14. Note that the execution of this program results in the execution of a method corresponding to the program. Furthermore, when the transparent QR code reading process is performed, the infrared light emitting unit 24 is in a state of emitting infrared light.

[0076] First, in step S100, a trial number N is set. The trial number N is the number of times to attempt to recognize the transparent QR code 10. That is, when the camera 22 starts capturing an image of the transparent QR code 10, the QR code recognition unit 34 performs a recognition process for the transparent QR code 10, and if the transparent QR code 10 cannot be recognized even after the recognition process has been performed more than N times, the recognition fails.

[0077] In addition to setting the trial number N, various settings may be made that are suitable for recognizing the transparent QR code 10. Here, the various settings include, for example, a resolution setting and a zoom magnification setting for the camera 22.

[0078] In the next step 102, the function of the camera 22 is used to measure the environment in which the transparent QR code 10 is read, in other words, the illuminance around the mobile terminal device 14.

[0079] In the next step 104, the photography location determination unit 36 ​​determines whether the location where the transparent QR code 10 was photographed is indoors or outdoors, based on the illuminance measured in step 102. Note that even if the location is actually outdoors, it may be determined to be indoors in step 104 if the illuminance is low. Even in such a case, there is little effect of sunlight on the reading of the transparent QR code 10, so it is not a problem if it is determined to be indoors. If the photography location is determined to be indoors in step 104, the process proceeds to step 106, and if the photography location is determined to be outdoors, the process proceeds to step 110.

[0080] In step 106, the guidance unit 38 sets the image display for indoor use. The image display for indoor use is, for example, a process of enlarging the bottom right corner of the touch panel display 20.

[0081] In the next step 108, the guiding unit 38 guides the operator to adjust the indoor shooting distance, and the process proceeds to step 114. The indoor shooting distance is, for example, 11 cm. The indoor shooting distance is pre-stored in the storage unit 32, and the guiding unit 38 causes the touch panel display 20 to display this value, for example.

[0082] If it is determined in step 104 that the photographing location is outdoors, the process proceeds to step 110, in which the guiding unit 38 sets the image display for outdoors. The image display for indoors is, for example, a process of enlarging the upper left corner of the touch panel display 20.

[0083] In the next step 116, the guiding unit 38 guides the operator to adjust the outdoor shooting distance, and the process proceeds to step 114. The outdoor shooting distance is, for example, 6 cm. The outdoor shooting distance is pre-stored in the storage unit 32, and the guiding unit 38 displays these values ​​on the touch panel display 20, for example.

[0084] In step 114, the QR code recognition unit 34 sets the trial number n to one.

[0085] In the next step 116 , the QR code recognition unit 34 performs a recognition process for the transparent QR code 10 from the image captured by the camera 22 .

[0086] In the next step 118, the QR code recognition unit 34 determines whether the recognition process of the transparent QR code 10 has been successful, and if the determination is affirmative, the transparent QR code reading process is terminated. If the determination is negative, the process proceeds to step 120.

[0087] In step 120, the QR code recognition unit 34 determines whether the trial number n is less than the trial number N. If the determination is affirmative, the process proceeds to step 124. On the other hand, if the determination is negative, the process proceeds to step 122.

[0088] In step 122, the QR code recognition unit 34 increments the trial number n by one, and then the process proceeds to step 116, where the QR code recognition unit 34 repeats the recognition process.

[0089] In step 124, the QR code recognition unit 34 determines the distortion of the transparent QR code 10 photographed by the camera 22, and if the distortion is small, the process proceeds to step 126. On the other hand, if the distortion is large, the process proceeds to step 128.

[0090] In step 126, the guiding unit 38 guides the operator to increase the imaging angle, and the process returns to step 114. The guiding unit 38, for example, displays a message on the touch panel display 20 to prompt the operator to increase the imaging angle, or outputs the message by voice.

[0091] In step 128, the guiding unit 38 guides the operator to reduce the imaging angle, and the process returns to step 114. The guiding unit 38, for example, displays a message on the touch panel display 20 or outputs the message by voice to prompt the operator to reduce the imaging angle.

[0092] If recognition of the transparent QR code 10 fails, the guidance unit 38 may guide the operator to make other adjustments, such as adjusting the shooting distance, in addition to adjusting the shooting angle.

[0093] As another example of adjustment, the guidance process executed by the guidance unit 38 guides the photographer in the shooting direction so that sunlight does not illuminate the transparent QR code 10 when the transparent QR code 10 is photographed outdoors and the transparent QR code 10 is not recognized even though it is photographed. When the transparent QR code 10 is photographed outdoors, it is affected by the infrared rays contained in sunlight, as described above. Therefore, if the transparent QR code 10 is not recognized when photographed outdoors, the influence of sunlight may be significant. Therefore, the operator is guided in the shooting direction to mitigate the influence of infrared light contained in sunlight.

[0094] 6 shows the flow of the above-mentioned guidance process. First, after step 120 shown in FIG.

[0095] In the next step 200, the photography location determination unit 36 ​​determines whether the photography location of the transparent QR code 10 was indoors or outdoors based on the illuminance measured in step 102. If the photography location is determined to be indoors in step 200, the process returns to step 114, and if the photography location is determined to be outdoors, the process proceeds to step 202.

[0096] In step 202, the guiding unit 38 guides the photographer to change the shooting orientation, and the process returns to step 114. The guiding unit 38, for example, displays a message on the touch panel display 20 or outputs an audio message to prompt the operator to change the orientation with respect to the sun. This orientation is calculated based on, for example, GPS information, latitude and longitude information, and time information, and an appropriate body orientation of the photographer to reduce the influence of sunlight is displayed on the touch panel display 20. Alternatively, a message such as "Please change the orientation of your body with respect to the sun" may be displayed or output as an audio message without calculating an appropriate body orientation of the photographer.

[0097] As described above, the mobile terminal device 14 of this embodiment is a QR code reader that reads the transparent QR code 10, which is not visible with visible light, by illuminating it with light of a predetermined wavelength other than visible light. In the mobile terminal device 14, the guidance unit 38 guides the operator in performing a photographing operation to perform a photograph that reduces the effects of infrared light, and the camera 22 photographs the transparent QR code 10 while the infrared light irradiation unit 24 irradiates infrared light, thereby reading the transparent QR code 10. In this way, the mobile terminal device 14 of this embodiment can read the transparent QR code 10.

[0098] Although the present disclosure has been described using the above-mentioned embodiments, the technical scope of the present disclosure is not limited to the scope described in the above-mentioned embodiments. Various modifications or improvements can be made to the above-mentioned embodiments without departing from the gist of the disclosure, and such modifications or improvements are also included in the technical scope of the present disclosure.

[0099] In the above embodiment, the portable terminal device 14 is described as including the infrared light irradiator 24 that irradiates infrared light, but the present disclosure is not limited to this. The infrared light irradiator 24 may not be directly provided in the portable terminal device 14, and may have a configuration different from that of the portable terminal device 14.

[0100] In the above embodiment, the transparent QR code 10 is described as being readable by infrared light, but the present disclosure is not limited to this. The transparent QR code 10 may be readable by light other than infrared light, for example, light with a wavelength in the ultraviolet range (ultraviolet light), as long as it can be read by light with a wavelength other than visible light. Ultraviolet light is also contained in sunlight, and presents the same issues as infrared light.

Claims

1. An information code reading device (14) that reads an information code (10) that cannot be seen with visible light by illuminating it with light of a predetermined wavelength other than visible light, comprising: an imaging unit (22) that images a subject; an irradiation unit (24) that irradiates the light of the predetermined wavelength; and a guidance unit (38) that guides an operator in performing a photography operation to take a photograph that reduces the effects of light of the predetermined wavelength when photographing the information code with the imaging unit.

2. An information code reading device as described in claim 1, wherein the guidance unit guides the operator's photographing operation so that the photographing position of the information code by the photographing unit is a predetermined position based on the positional relationship between the photographing unit and the irradiation unit.

3. An information code reading device as described in claim 2, further comprising a display unit (20) that displays the image captured by the photographing unit, and the guidance unit causes a partial area of ​​the image captured by the photographing unit to be enlarged and displayed on the display unit so that the photographing position of the information code by the photographing unit becomes the specified position.

4. An information code reading device as described in claim 1 or claim 2, further comprising a location determination unit (36) that determines whether the location where the information code was photographed is indoors or outdoors, and the guidance unit guides the operator in the photographing operation based on the determination result by the location determination unit.

5. An information code reading device as described in claim 4, wherein the guidance unit guides the operator's photographing operation so that the photographing position of the information code by the photographing unit is a predetermined position based on the determination result by the location determination unit.

6. An information code reading device as described in claim 4, wherein the guidance unit guides the operator's photographing operation so that the distance between the information code and the photographing unit becomes a distance based on the result of determination by the location determination unit.

7. An information code reader according to claim 6, wherein the distance is shorter when the information code is photographed outdoors than when the information code is photographed indoors.

8. An information code reading device according to claim 1 or 2, wherein the guidance section guides the operator in performing a photographing operation so as to adjust the angle between the photographing section and the information code.

9. An information code reading device as described in claim 8, wherein the guidance unit guides the operator in the photographing operation so as to increase the angle when the distortion of the information code photographed by the photographing unit is relatively small, and to decrease the angle when the distortion is relatively large.

10. An information code reading device as described in claim 2, wherein the guidance unit guides the photographer in a direction to photograph the information code so that sunlight does not illuminate the information code when the information code is photographed outdoors and the information code is not recognized despite being photographed.

11. A method for reading an information code that cannot be seen with visible light by illuminating it with light of a predetermined wavelength other than visible light, wherein a guidance unit guides an operator in a photographing operation to take a photograph that reduces the influence of light of the predetermined wavelength, and an imaging unit photographs the information code while an illumination unit irradiates the light of the predetermined wavelength, thereby reading the information code.

12. An information code reading program possessed by an information code reading device that reads information codes that cannot be seen with visible light by shining light of a specified wavelength other than visible light, the information code reading program causing a computer to function as a guidance unit that guides an operator in performing a photographing operation so as to perform a photographing operation that reduces the effects of light of the specified wavelength when photographing the information code with a photographing unit that photographs a subject.

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